Why would project scenes look darker on different machine?

One of the artists on my team is having a problem with all the scenes in the project appearing way darker on his PC. This appears to be mostly lightmapped objects but scenes without a bake yet also appear very dark, and different. It is a drastic change (image included) and basically makes Lightmapping impossible on his side. Could there be some Unity engine setting that is causing this? Could this be related to shaders? Has anyone seen anything like this? We are both on 5.5.0p1. Both running off the same Git repo. I have tried to go through every settings menu I could think of and everything appear to be the same on our machines. I cannot find the source of this so I hope someone here can steer me in the right direction.